build: introduce luci-base

[project/luci.git] / modules / base / luasrc / luasrc / template.lua

diff --git a/modules/base/luasrc/luasrc/template.lua b/modules/base/luasrc/luasrc/template.lua
new file mode 100644 (file)
index 0000000..72127d1
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+++ b/modules/base/luasrc/luasrc/template.lua
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+--[[
+LuCI - Template Parser
+
+Description:
+A template parser supporting includes, translations, Lua code blocks
+and more. It can be used either as a compiler or as an interpreter.
+
+FileId: $Id$
+
+License:
+Copyright 2008 Steven Barth <steven@midlink.org>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at 
+
+       http://www.apache.org/licenses/LICENSE-2.0 
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+]]--
+
+local util = require "luci.util"
+local config = require "luci.config"
+local tparser = require "luci.template.parser"
+
+local tostring, pairs, loadstring = tostring, pairs, loadstring
+local setmetatable, loadfile = setmetatable, loadfile
+local getfenv, setfenv, rawget = getfenv, setfenv, rawget
+local assert, type, error = assert, type, error
+
+--- LuCI template library.
+module "luci.template"
+
+config.template = config.template or {}
+viewdir = config.template.viewdir or util.libpath() .. "/view"
+
+
+-- Define the namespace for template modules
+context = util.threadlocal()
+
+--- Render a certain template.
+-- @param name         Template name
+-- @param scope                Scope to assign to template (optional)
+function render(name, scope)
+       return Template(name):render(scope or getfenv(2))
+end
+
+
+-- Template class
+Template = util.class()
+
+-- Shared template cache to store templates in to avoid unnecessary reloading
+Template.cache = setmetatable({}, {__mode = "v"})
+
+
+-- Constructor - Reads and compiles the template on-demand
+function Template.__init__(self, name) 
+
+       self.template = self.cache[name]
+       self.name = name
+       
+       -- Create a new namespace for this template
+       self.viewns = context.viewns
+       
+       -- If we have a cached template, skip compiling and loading
+       if not self.template then
+
+               -- Compile template
+               local err
+               local sourcefile = viewdir .. "/" .. name .. ".htm"
+
+               self.template, _, err = tparser.parse(sourcefile)
+
+               -- If we have no valid template throw error, otherwise cache the template
+               if not self.template then
+                       error("Failed to load template '" .. name .. "'.\n" ..
+                             "Error while parsing template '" .. sourcefile .. "':\n" ..
+                             (err or "Unknown syntax error"))
+               else
+                       self.cache[name] = self.template
+               end
+       end
+end
+
+
+-- Renders a template
+function Template.render(self, scope)
+       scope = scope or getfenv(2)
+       
+       -- Put our predefined objects in the scope of the template
+       setfenv(self.template, setmetatable({}, {__index =
+               function(tbl, key)
+                       return rawget(tbl, key) or self.viewns[key] or scope[key]
+               end}))
+       
+       -- Now finally render the thing
+       local stat, err = util.copcall(self.template)
+       if not stat then
+               error("Failed to execute template '" .. self.name .. "'.\n" ..
+                     "A runtime error occured: " .. tostring(err or "(nil)"))
+       end
+end